1. Field of the Invention
The present invention relates generally to electronics product screening inspection architecture and, more particularly, to a method for discriminating capacitor quality based on capacitor charge characteristics upon application of a direct current (DC) voltage thereto.
2. Description of the Prior Art
Generally, a well known method for measurement of the dielectric resistance of capacitors is to measure leakage current (charge current) of a fully charged capacitor while applying thereto a DC voltage. Obviously, good products of expected quality permit less leakage current to flow therethrough.
One prior known approach to the charge current measurement of this type is a measurement scheme as set forth in Japanese Industrial Standards (JIS) C5102. This scheme might require a measurement time duration of approximately sixty (60) seconds due to the necessity of measuring current values of capacitors which are sufficiently charged. However, as the need for electronic equipment or apparatus to offer further cost reduction and reliability enhancement increases, electronic parts or components, including but not limited to capacitors, are likewise required to have further increases in productivity and quality. Prior known measurement methods which require an increased length of measurement time per capacitor are incapable of meeting such needs.
One typical approach to simplified capacitor quality discrimination is to determine whether a capacitor under inspection is good or defective by applying thereto a voltage and then measuring a current value after the elapse of a specified time duration, such as several seconds, and then to compare the resulting measured current value to a predefined threshold value. However, a quality discrimination method using such point data does not result in accurate and reliable discrimination. For, although the data at the time of measurement may indicate a good capacitor, the data change afterwards may indicate that the capacitor is, in fact, defective.